Apparatus for facilitating printing cassette replacement

ABSTRACT

A transfer cart (10) facilitates exchange of printing cassettes in a printing press (14), the printing cassettes have respective images to be printed. A first shelf (70) of the transfer cart (10) receives a replacement printing cassette (12b) from a cassette storage facility (16). The transfer cart (10) has a base (60) with wheels (62) such that the transfer cart can be moved from the storage facility (16) to a location adjacent to the printing press (14). A second shelf (74) of the transfer cart (10) receives a replaceable printing cassette (12a) from the printing press (14) while the replacement cassette (12b) is retained on the first shelf (70). A lift mechanism (80) moves the first and second shelves (70, 74) between a position in which the second shelf can receive the replaceable cassette (12a) from the printing press (14) while the first shelf retains the replacement cassette (12b) and a position in which the printing press can receive the replacement cassette from the first shelf while the second shelf retains the replaceable cassette received from the printing press. Only a single round trip of the transfer cart (10) between the storage facility (16) and the printing press (14) is needed to exchange the cassettes.

BACKGROUND OF THE INVENTION

The present invention relates to printing presses, and particularly tooffset printing presses which have one or more cylinders that arereplaced to change the image to be printed by the printing press.

An offset printing press comprises plate, blanket and impressioncylinders for rotation about respective axes. The plate cylinder has animage which is to be printed. Ink is applied to the image, and an inkimage is transferred from the plate cylinder to the blanket cylinder andsubsequently to the material to be printed as the material passesthrough a nip defined between the blanket and impression cylinders.

It is known to replace the plate cylinder within the printing press withanother plate cylinder when the image to be printed is to be changed.During the plate cylinder replacement, the plate cylinder within theprinting press is removed from the printing press and moved from theprinting press to a storage facility. The removed plate cylinder isstored in the storage facility for later use again in the printingpress. A replacement plate cylinder is removed from the storage facilityand moved to the printing press. The replacement plate cylinder is thenmounted into the printing press and the printing press is enabled for asubsequent printing run during which the image on the replacement platecylinder is printed. The plate cylinder is part of an assembly known asa printing cassette.

SUMMARY OF THE INVENTION

The present invention is an apparatus for facilitating removal of oneprinting cassette from a printing press and mounting of a replacementprinting cassette in the printing press. The printing cassettes includeplate cylinders which have respective images to be printed on materialduring operation of the printing press. A first holding means of theapparatus receives a replacement printing cassette from a cassettestorage facility. A transport means carries the first holding means andthe replacement printing cassette received by the first holding meansfrom the cassette storage facility to a transfer location adjacent tothe printing press.

A second holding means receives a printing cassette from a cassettelocation in the printing press while the replacement printing cassetteis retained by the first holding means. A mover means moves the firstand second holding means between first and second positions. In thefirst position the second holding means can receive the printingcassette from the cassette location in the printing press while thefirst holding means retains the replacement printing cassette. In thesecond position the cassette location in the printing press can receivethe replacement printing cassette from the first holding means while thesecond holding means retains the printing cassette received from theprinting press.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the present invention will become apparent to thoseskilled in the art to which the present invention relates from readingthe following specification with reference to the accompanying drawings,in which:

FIG. 1 is a schematic view of a printing facility, partially in section,and a printing cassette transfer cart in accordance with the presentinvention;

FIG. 2 is a view taken along line 2--2 in FIG. 1;

FIG. 3 is a schematic perspective view of the transfer cart shown inFIG. 2;

FIG. 4 is a view taken along line 4--4 in FIG. 3; and

FIGS. 5-7 are views similar to FIG. 2, but with parts in differentpositions.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A printing cassette transfer cart 10 in accordance with the presentinvention and an associated printing facility are schematicallyillustrated in FIG. 1. The transfer cart 10 facilitates exchange ofprinting cassettes between a printing press 14 and a cassette storagefacility 16 within the printing facility. FIG. 1 illustrates threecassettes 12a, 12b, and 12c. Cassette 12a is located in the printingpress 14. Cassette 12c is located in the cassette storage facility 16.Cassette 12b is located on the transfer cart 10 adjacent the printingpress 14.

The printing press 14 may have any suitable construction and ispreferably an offset printing press. A frame 18 of the printing press 14has two side frames 20 and 22 which are spaced apart and parallel toeach other. Each of the side frames 20, 22 has an opening 24. Theopenings 24 are generally rectangular in shape and are aligned with eachother.

A printing cassette location 26 is defined within the frame 18 of theprinting press 14 between the side frames 20, 22 at the openings 24. Acassette loading platform 28 (FIG. 2) extends from the side frame 22,adjacent the lower edge of the opening 24. A guide rail 30 extends alongthe loading platform 28 and between the side frames 20, 22.

Each cassette 12a-12c has the same structural features and has the samefunction within the printing press 14. Each cassette includes twocassette sides 36 and 38. The cassette sides 36, 38 are plate-like andhave the same shape as the openings 24 in the side frames 20, 22. When acassette is in the printing press 14, the cassette sides 36, 38 arelocated in the openings 24 and are locked in place relative to the frame18 by a suitable lock means (not shown).

Each cassette also includes a plate cylinder 40 located between thecassette sides 36, 38. The plate cylinder 40 is journalled for rotationabout an axis relative to the cassette sides 36, 38, and thus rotatesrelative to the frame 18. An image is on the outer side of the platecylinder 40 and the image corresponds to the image to be printed. Theimage may be formed on the plate cylinder circumference or may be on athin printing plate wrapped around the plate cylinder as is known. Eachcassette 12a-12c has a distinct image to be printed.

Each cassette also includes a blanket cylinder 42 located between thecassette sides 36, 38. The blanket cylinder 42 is journalled forrotation relative to the cassette sides, and thus rotates relative tothe frame 18. A resilient blanket is mounted on the outer side of theblanket cylinder 42.

The printing press 14 has an inker assembly 32. The plate cylinder 40 isadjacent to the inker assembly 32 when the cassette is in the printingpress 14. A motor and gears (not shown) rotate the plate and blanketcylinders 40 and 42 during a printing run. During rotation of the plateand blanket cylinders 40 and 42, ink is applied by the inker assembly 32to the image on the plate cylinder 40. The ink image is transferred fromthe plate cylinder 40 to the blanket on the blanket cylinder 42, as willbe understood by those skilled in the art.

An impression cylinder 34 is mounted between the side frames 20, 22 andis movable to a location in close proximity to the blanket cylinder 42.A nip 44 is defined by and between the adjacent blanket and impressioncylinders 42 and 34. A web of printing stock material 46 (FIG. 1) ismoved through the nip 44 (FIG. 2) during a printing run, and the inkimage is transferred from the blanket cylinder 42 to the stock material.

The cassette storage facility 16 (FIG. 1) may have any suitableconstruction for storing a plurality of cassettes. For example, thestorage facility 16 may have a plurality of shelves 52 (only one shown)for receiving the respective cassettes. Each of the shelves 52 has aguide rail 54 for guiding movement of the respective cassette onto andfrom the respective shelf 52.

A track 56 extends between the printing press 14 and the storagefacility 16, and has any suitable construction. For example, the track56 is illustrated (FIG. 1) as having a single pair of rails. However,the track 56 may have several branches to various areas of the storagefacility 16.

The transfer cart 10 may have any suitable construction. In thepreferred embodiment, the transfer cart 10 (FIG. 3) has a base 60 andfour wheels 62. Each wheel 62 is adjacent to a corner of the base 60 andis configured to roll upon the track 56. A manually engageable handle 64extends from the base 60. An operator 84 (FIG. 2) can grasp the handle64 and can push or pull the transfer cart 10 along the track 56 betweenthe printing press 14 and the storage facility 16.

A carriage 66 (FIG. 3) is located above the base 60 and has at least onevertical support post 68. A lower shelf 70 of the carriage 66 is fixedto a bottom of the support post 68. The lower shelf 70 is planar and aguide rail 72 extends along the top of the lower shelf. An upper shelf74 of the carriage 66 is fixed to the support post 68 and is locatedabove the lower shelf 70. The upper shelf 74 is similar to the lowershelf 70 and a guide rail 76 extends along the top of the upper shelf.

The support post 68 is located on one side of the shelves 70, 74 (FIG.4) and a cassette (not shown in FIG. 4) can be slid onto or off of arespective shelf from either end of the respective shelf. The guiderails 72, 76 guide the sliding movement. Both shelves 70, 74 of thecarriage 66 can receive a cassette and hold the cassette during movementof the transfer cart 10.

A lift mechanism 80 supports and carries the carriage 66 on the base 60.The lift mechanism 80 can move the carriage 66 relative to the base 60.The movement of the carriage 66 by the lift mechanism 80 is in avertical direction.

The lift mechanism 80 may have two pairs of scissor-like cross-members.Each pair of cross-members (FIG. 3) has lower ends guided along portionsof the base 60 and upper ends guided along portions of the lower shelf70. A motor 86 drives the lower ends of the cross-members relativelytoward or away from each other along the base 60.

The upper ends of the cross-members move vertically relative to the base60 when the lower ends are moved. The carriage 66 is moved verticallywith the upper ends of the cross-members. A control pad 82 controls theoperation of the motor 86 of the lift mechanism 80. The control pad 82is located at a suitable location on the transfer cart 10. The controlpad 82 is operable by the operator 84 (FIG. 2) to cause the carriage 66to move vertically.

When it is desired to replace the cassette 12a (FIG. 1) in the printingpress 14 with the cassette 12b, the operator 84 moves the transfer cart10 to an appropriate location at the storage facility 16. The operator84 moves the desired cassette 12b from its respective shelf 52 in thestorage facility 16 onto one of the shelves 70, 74 of the carriage 66.In the illustrated embodiment, the cassette 12b is moved onto the lowershelf 70 (FIG. 2). The operator 84 moves the transfer cart 10 along thetrack 56 from the storage facility 16 to a position adjacent to theprinting press 14. This cart movement is a delivery segment of a roundtrip of the transfer cart 10 between the storage facility 16 and theprinting press 14. During the cart movement, the wheels 62 roll alongthe track 56 and the carriage 66, with the supported cassette 12b, iscarried by the lift mechanism 80 and the base 60.

When the transfer cart 10 is at a location adjacent to the printingpress 14, the one shelf 70, 74 which does not contain the cassette 12bis aligned with the loading platform 28 by moving the carriage 66vertically via the lift mechanism 80. In the illustrated example, theupper shelf 74 is aligned with the loading platform 28 (FIG. 2).Operation of the printing press 14 is ceased, and the printing press 14is readied for exchange of the cassettes. In particular, the impressioncylinder 34 is moved away from the blanket cylinder 42 and the lockmeans holding the cassette 12a is unlocked.

The operator 84 (FIG. 5) slides the cassette 12a along the guide rail 30out from the printing press 14, across the loading platform 28 and ontothe upper shelf 74. A handle 90 is provided on the cassette side 38 tofacilitate movement of the cassette. The cassette 12a is moved along theupper shelf 74 and along its guide rail 76 until the cassette 12a iscompletely removed from the printing press 14 and completely located onthe upper shelf 74. The removal of the cassette 12a from the printingpress 14 and the movement of the cassette 12a onto the upper shelf 74 isdone while the cassette 12b remains on the lower shelf 70. The operator84 (FIG. 6) then operates the control pad 82 to cause the lift mechanism80 to raise the carriage 66 to align the lower shelf 70 with the loadingplatform 28.

The replacement cassette 12b (FIG. 7) is moved by the operator 84 alongthe lower shelf 70 and its guide rail 76 onto the loading platform 28.The replacement cassette 12b is moved along the guide rail 30 into theprinting press 14 until its cassette sides 36, 38 are located within theopening in the side frames 20, 22, respectively. The movement of thecassette 12b from the lower shelf 70 and into the printing press 14 isdone while the cassette 12a remains on the upper shelf 74.

The cassette 12b is locked in position relative to the frame 18 by thelock means and the printing press 14 is readied for a new printing run.The impression cylinder 34 is moved into close proximity with theblanket cylinder 42 of the cassette 12b and the stock material 46 is fedthrough the nip 44 defined between the impression and blanket cylinders.The printing run is started, and the image on the plate cylinder 40 ofthe cassette 12b is printed onto the stock material 46.

The operator 84 can lower the carriage 66 with the cassette 12a on theupper shelf 74 for movement of the transfer cart 10 away from theprinting press 14 to the storage facility 16. This cart movement is areturn segment of the round trip of the transfer cart 10 between thestorage facility 16 and the printing press 14. At the storage facility16, the cassette 12a is moved from the upper shelf 74 of the carriage 66onto a respective shelf 52 of the storage facility for later use.Maintenance work, such as cleaning and/or blanket replacement can beperformed on the cassette 12a away from the printing press.

The transfer cart 10 increases the efficiency with which an exchange ofcassettes, and a change of print images, can be accomplished, in thatminimum handling of the cassettes needs to be performed in order toexchange cassettes.

From the above description of the invention, those skilled in the artwill perceive improvements, changes and modifications. Suchimprovements, changes and modifications within the skill of the art areintended to be covered by the appended claims.

Having described the invention, the following is claimed:
 1. Anapparatus for facilitating exchange of printing cassettes in a printingpress, the printing cassettes having respective images to be printed onmaterial during operation of the printing press, said apparatuscomprising:first holding means for receiving a replacement printingcassette from a cassette storage facility; transport means for carryingsaid first holding means and the replacement printing cassette receivedby said first holding means from the cassette storage facility to atransfer location adjacent to the printing press; second holding meansfor receiving a replaceable printing cassette from a cassette locationin the printing press while the replacement printing cassette isretained by said first holding means, said second holding means beinglocated directly above said first holding means; and mover means forsimultaneously moving said first and second holding means in a verticaldirection between a first position in which said second holding meanscan receive the replaceable printing cassette from the cassette locationin the printing press while said first holding means retains thereplacement printing cassette directly underneath said second holdingmeans and a second position in which the cassette location in theprinting press can receive the replacement printing cassette from saidfirst holding means while said second holding means retains saidreplaceable printing cassette received from the printing press directlyabove said first holding means.
 2. An apparatus as set forth in claim 1,wherein said first and second holding means are first and secondshelves, respectively.
 3. An apparatus as set forth in claim 1, whereinsaid transport means includes a base which has a plurality of wheels. 4.An apparatus as set forth in claim 3, wherein said wheels are movablealong a track which extends between the cassette storage facility andthe printing press.
 5. An apparatus as set forth in claim 3, including amanually engageable handle extending from said base for engagement by anoperator.
 6. An apparatus as set forth in claim 1, including a controlmeans for controlling operation of said mover means.
 7. An apparatus forfacilitating exchange of printing cassettes in a printing press, theprinting cassettes having respective images to be printed on materialduring operation of the printing press, said apparatus comprising:firstholding means for receiving a replacement printing cassette from acassette storage facility; transport means for carrying said firstholding means and the replacement printing cassette received by saidfirst holding means from the cassette storage facility to a transferlocation adjacent to the printing press; second holding means forreceiving a replaceable printing cassette from a cassette location inthe printing press while the replacement printing cassette is retainedby said first holding means, said second holding means being locateddirectly underneath said first holding means; and mover means forsimultaneously moving said first and second holding means in a verticaldirection between a first position in which said second holding meanscan receive the replaceable printing cassette from the cassette locationin the printing press while said first holding means retains thereplacement printing cassette directly above said second holding meansand a second position in which the cassette location in the printingpress can receive the replacement printing cassette from said firstholding means while said second holding means retains said replaceableprinting cassette received from the printing press directly underneathsaid first holding means.
 8. An apparatus as set forth in claim 7,wherein said first and second holding means are first and secondshelves, respectively.